Finisher for an image forming apparatus

Abstract

A finisher for use with a copier, printer or similar image forming apparatus for stapling or otherwise finishing paper sheets sequentially driven out of the apparatus. A paper sheet is introduced in a stapling section of a stapling device by being switched back, while being accurately guided by a guide member having a sufficient length. The stapling device is movable, independently of jogger fences which position paper sheets, to a particular position which is optimal for the size of stacked paper sheets and the position in which they are used. When a staple error detector detects a stapling error, a discharge path in use is switched over to another path. When a stapled paper stack is discharged, it is deformed in a wave-like configuration in a direction perpendicular to an intended direction of transport to be provided with a certain degree of rigidity. This allows the stapled paper stack to be driven out stably, epecially without being loosened at the discharge side. A jam detector detects a failure in the discharge of paper sheets in a discharging device with accuracy. A stapled paper stack is directly driven out of the stapling device without the intermediary of an exclusive path.

What is claimed is: 
     
       1. A finisher for stapling sheets sequentially driven out of an apparatus, comprising: a frame;   a first tray disposed in an upper portion of said frame;   stapling means located in a lower portion of said frame;   an inlet for receiving a paper sheet driven out of the apparatus;   a first path extending from said inlet to said first tray;   a second path extending from said inlet to said stapling means;   a second tray disposed below said first tray;   discharging means directly connected to said second tray for discharging a stack of paper sheets having been stapled by said stapling means onto said second tray;   said stapling means comprising a paper receiver, a stapling device for stapling paper sheets loaded on said paper receiver and jogger fences for positioning sheets loaded on said paper receiver; and   wherein said discharging means includes a discharge belt directly connecting said stapling means and said second tray to each other, and holding means protruding from said discharge belt for holding a stapled stack of sheets at a side where said sheets are stapled.   
     
     
       2. A finisher as claimed in claim 1, wherein said jogger fences function as guide means when said discharging means dicharges the stapled stack of sheets. 
     
     
       3. A finisher as claimed in claim 1, wherein said discharge belt extends aslant in a nearly vertical direction. 
     
     
       4. A finisher as claimed in claim 1, wherein said discharging means further comprises rigidity providing means for providing a stapled stack of sheet with rigidity by deforming said stack in a wave-like configuration in a direction perpendicular to an intended direction of sheet transport. 
     
     
       5. A finisher as claimed in claim 4, wherein said rigidity providing means comprises pressing means for pressing a stapled stack of sheets in different positions and in a direction perpendicular to a surface of said stapled stack. 
     
     
       6. A finisher as claimed in claim 1, further comprising staple error detecting means associated with said discharging means and said stapling means for detecting a stapling error. 
     
     
       7. A finisher as claimed in claim 6, further comprising path control means for replacing said first and second paths with a path to a second tray in response to an output of said staple error detecting means representative of a stapling error. 
     
     
       8. A finisher as claimed in claim 1, further comprising jam detecting means associated with said discharging means for detecting an error in the discharge of sheets.